However, it is the latest available. If you are running an older "JNC" or early "JFY" release, moving to JPN1 is definitely a "better" move for stability. If you are looking for the absolute latest features or security patches for the 3700 series (which is now End-of-Life), you would actually want to look at the 15.3(3)JY train (specifically JY11 or later) or the 8.10 train (if using Mobility Express).
Users who search this exact string often see an error like: